This invention relates to a method and an apparatus for recuperating heat from, and imparting kinetic energy to, a gas or gases. More particularly, this invention relates to a method and an apparatus for heat-pulsed recuperation of heat energy, through the preheating of reactants in a high-temperature combustion process or the like.
Many high temperature industrial combustion processes end up with products of combustion at a temperature in excess of 1400 degrees Kelvin (.degree.K.). At such a temperature, half or more of the available heat energy of the combustion products remains unutilized. While recuperation of this heat energy is desirable, the combustion gases are typically available at a pressure minimally above atmospheric pressure. As a result, the gases lack the static pressure needed for them to be passed without added propulsion through an efficient energy recovery device. Propulsion devices such as fans or blowers could conceivably provide such propulsion, but fans and blowers which could withstand the high temperature of the gases would appear to be prohibitively expensive or beyond the state of the art. Moreover, the gases are often corrosive, further limiting the conceivably useful propulsion mechanisms to those having materials capable of withstanding a corrosive atmosphere.
Because of the high-temperature resistance and corrosion resistance limitations on propulsion devices, recourse for energy recovery is typically had to tall chimneys or flues. The chimneys and flues attempt to provide a buoyant force sufficient to move the gases through open regenerator checkers and open spaces of radiant recuperators. Such tall chimneys and flues result in low gas velocities, low heat transfer rates, and minimal control over effluents for cleaning and detoxification. Thus, a need exists for improved recuperation of heat energy from the products of high temperature, industrial combustion processes and the like, and improved means for imparting kinetic energy to such products.